Method and system for establishing wireless local area network link between portable terminals

ABSTRACT

A method of establishing a WLAN link between portable terminals using a cellular network and a sound, the method including: transmitting a connection request message including a first partial security key being a portion of a first security key to a second portable terminal through a cellular network by a first portable terminal; outputting a sound including a second partial security key being a remaining portion of the first security key after transmitting the connection request message; receiving a request of a WLAN connection including a second security key from the second portable terminal having received the sound through a WLAN; and establishing the WLAN link with the second portable terminal when the second security key corresponds to the first security key.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority from Korean Patent Application No.10-2012-0038408, filed on Apr. 13, 2012 in the Korean IntellectualProperty Office, the entire disclosure of which is hereby incorporatedby reference.

BACKGROUND

1. Field

Apparatuses and methods consistent with exemplary embodiments relate tocommunicating through a wireless local area network (WLAN), and moreparticularly, to establishing a WLAN link between portable terminalswith improved security stability while supporting convenience of WLANconnection.

2. Description of the Related Art

In recent years, with development of digital technology, mobileterminals, such as Personal Digital Assistant (PDA), electronicorganizer, smart phone, tablet Personal Computer (PC), capable ofprocessing communication and private information have been widely used.The portable terminals have various functions such as voice call, imagecall, message transmission such as Short Message Service(SMS)/Multimedia Message Service (MMS), electronic organizer,photographing, e-mail transceiving, broadcast playback, moving imageplayback, Internet, electronic commerce, music playback, schedulemanagement, Social Networking Service (SNS), friend finder service,messenger, dictionary, game, WLAN link establishment, etc.

Meanwhile, the Institute of Electrical and Electronics Engineers (IEEE)802.11 WLAN technology has made rapid progress, and the number of theWLAN users has been steadily increasing. Various encryption andauthentication methods have been proposed to ensure security stabilityin WLAN communication.

For example, Wi-Fi Alliance (WFA) suggests Wi-Fi Protected Setup (WPS)to improve restriction on use. The WPS mainly includes a PersonalIdentification Number (PIN) method and a Push Button Configuration (PBC)method, and the PIN method must be legally implemented.

When using the WPS PIN method, the user inputs only a PIN number of 4 to8 digits without selecting a security method to establish securityconnection. However, the user generates or inputs a PIN number through acomplicated setting menu.

When a PBC button is implemented by software in the WPS PBC method, theuser needs to find and press a button through a complicated menu. Whenthe PBC button is implemented by hardware, if the user mistakes anotherbutton (e.g., reset button) for the PBC button, the device mayerroneously operate. In addition, when a plurality of devices isconnected to each other through WLAN, and the user wishes to operate allof the devices, the procedure becomes complicated, cumbersome, andtime-consuming.

SUMMARY

Exemplary embodiments may address at least the above problems and/ordisadvantages and other disadvantages not described above. Also,exemplary embodiments are not required to overcome the disadvantagesdescribed above, and an exemplary embodiment may not overcome any of theproblems described above.

One or more exemplary embodiments provide a method of establishing aWLAN link between portable terminals capable of reinforcing securitystability while supporting simple and rapid WLAN connection, and asystem thereof.

One or more exemplary embodiments also provide a method capable ofestablishing a WLAN link between portable terminals using a cellularnetwork and a sound output from the portable terminal, and a system forsupporting the same.

One or more exemplary embodiments also provide a method of establishinga WLAN link between portable terminals capable of improving convenience,usability, and competitive force of the portable terminals byimplementing optimal environments for establishing the WLAN link, and asystem thereof.

In accordance with an aspect of an exemplary embodiment, there isprovided a method of establishing a WLAN link in a portable terminal,the method including: transmitting a connection request messageincluding a first partial security key being a part of a security key toa second portable terminal through a cellular network by a firstportable terminal; outputting a sound including a second partialsecurity key being a remaining of the second security key by the firstportable terminal; acquiring the first partial security key through theconnection request message and acquiring the second partial security keythrough the sound by the second portable terminal; requesting a WLANconnection to the first portable terminal using the first partialsecurity key and the second partial security key by the second portableterminal; and establishing the WLAN link with the second portableterminal by the first portable terminal in response to a request of theWLAN connection.

In accordance with an of another exemplary embodiment, there is provideda method of establishing a WLAN link in a portable terminal, the methodincluding: transmitting a connection request message including a firstpartial security key being a part of a security key to a second portableterminal through a cellular network by a first portable terminal;outputting a sound including a second partial security key being aremaining of the first security key after transmitting the connectionrequest message; receiving a request of WLAN connection including asecond security key from the second portable terminal having receivedthe sound through a WLAN; and establishing the WLAN link with the secondportable terminal when the second security key corresponds to the firstsecurity key.

In accordance with an aspect of another exemplary embodiment, there isprovided a method of establishing a WLAN link in a portable terminal,the method including: receiving a connection request message from acontact server through a cellular network in a push scheme by a secondportable terminal; turning-on a microphone for receiving reception of asound output from a first portable terminal in response to theconnection request message; receiving the sound output from the firstportable terminal through the microphone; acquiring a first partialsecurity key according to the connection request message and a secondpartial security key according to the sound; combining the secondpartial security key with the first partial security key to acquire asecurity key; and requesting WLAN connection to the first portableterminal using the acquired security key.

In accordance with an aspect of another exemplary embodiment, there isprovided a computer-readable recording medium recording a program forexecuting the method by a processor.

In accordance with an aspect of another exemplary embodiment, there isprovided a system for establishing a WLAN link including: a firstportable terminal to initiate a service for establishing the WLAN linkand to output partial security keys divided from a first security keyfor the WLAN connection through a connection request message and asound, respectively; and a second portable terminal to turn-on amicrophone in response to reception of the connection request message,to receive the sound through the microphone, and to request WLANconnection to the first portable terminal using the connection requestmessage and partial security keys acquired from the sound.

In accordance with an aspect of another exemplary embodiment, there isprovided a portable terminal including: a memory to store at least oneprogram; and a controller to execute the at least one program to controlsuch that a first portable terminal establishes a WLAN link with asecond portable terminal, wherein the at least program includes commandsfor executing: transmitting a connection request message including afirst partial security key being a part of a security key to a secondportable terminal through a cellular network by a first portableterminal; outputting a sound including a second partial security keybeing a remaining of the first security key after transmitting theconnection request message; receiving a request of WLAN connectionincluding a second security key from the second portable terminal havingreceived the sound through a WLAN; and establishing the WLAN link withthe second portable terminal when the second security key corresponds tothe first security key.

In accordance with an aspect of another exemplary embodiment, there isprovided a portable terminal including: a memory to store at least oneprogram; and a controller to execute the at least one program to controlsuch that a first portable terminal establishes a WLAN link with asecond portable terminal, wherein the at least program includes commandsfor executing: receiving a connection request message from a contactserver through a cellular network in a push scheme by a second portableterminal; turning-on a microphone for receiving reception of a soundoutput from a first portable terminal in response to the connectionrequest message; receiving the sound output from the first portableterminal through the microphone; acquiring a first partial security keyaccording to the connection request message and a second partialsecurity key according to the sound; combining the second partialsecurity key with the first partial security key to acquire a firstsecurity key; and requesting WLAN connection to the first portableterminal using the acquired security key.

In accordance with an aspect of another exemplary embodiment, there isprovided a computer-readable recording medium recording a program thattransmits partial security keys divided from a first security keythrough a cellular network and a sound, respectively, combines thepartial security keys received through the cellular network and thesound with each other to generate a second security key, and establishesa wireless local area network link using the first security key and thesecond security key.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will become more apparent by describingcertain exemplary embodiments, with reference to the accompanyingdrawings, in which:

FIG. 1 is a schematic diagram illustrating a configuration of a systemfor describing an operation of establishing a WLAN link between portableterminals according to an exemplary embodiment;

FIG. 2 is a schematic diagram illustrating an example of a connectionrequest message format according to an exemplary embodiment;

FIG. 3 is a block diagram schematically illustrating a configuration ofa portable terminal according to an exemplary embodiment;

FIG. 4 is a signal flow chart illustrating a method of establishing aWLAN link between a first portable terminal and a second portableterminal according to an exemplary embodiment;

FIG. 5 is a flow chart illustrating a control method when a portableterminal operates as a transmitter portable terminal according to anexemplary embodiment;

FIGS. 6, 7, 8, and 9 are diagrams illustrating examples of an operationscreen of a first portable terminal according to an exemplaryembodiment;

FIG. 10 is a flow chart illustrating a control method when a portableterminal operates as a receiver portable terminal according to anexemplary embodiment; and

FIGS. 11, 12, and 13 are diagrams illustrating examples of an operationscreen of a second portable terminal according to an exemplaryembodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Certain exemplary embodiments are described in greater detail below withreference to the accompanying drawings.

In the following description, like drawing reference numerals are usedfor the like elements, even in different drawings. The matters definedin the description, such as detailed construction and elements, areprovided to assist in a comprehensive understanding of exemplaryembodiments. However, exemplary embodiments can be practiced withoutthose specifically defined matters. Also, well-known functions orconstructions are not described in detail since they would obscure theapplication with unnecessary detail.

An exemplary embodiment relates to a method and a system for connectingportable terminals to each other through a WLAN. An exemplary embodimentmay support WLAN based connection between portable terminals using acellular network and a sound. According to a WLAN connection method ofan exemplary embodiment, convenience for a user may be improved bysimplifying a procedure of the user according to WLAN connection whilereinforcing security stability during the WLAN connection betweenportable terminals. In an exemplary embodiment, for example, the soundincludes an audible frequency or a sound wave greater than the audiblefrequency, which refers to the sound below.

According to an exemplary embodiment, if a user of a transmitterportable terminal initiates a service for establishing the WLAN link, atleast two partial security keys divided from a security key may betransmitted to a receiver portable terminal. The receiver portableterminal combines partial security keys received through a cellularnetwork and a sound, and transmit the combined security key to thetransmitter portable terminal. Then, the transmitter portable terminalmay establish WLAN link between the transmitter portable terminal andthe receiver portable terminal by authenticating the receiver using itssecurity key and a received security key.

The portable terminal of an exemplary embodiment may include at leastone of a wireless communication network for a cellular network, that is,a mobile communication network and a WLAN communication interface for aWLAN. The cellular network of an exemplary embodiment may use varioustypes of networks such as 2nd Generation (2G), 3rd Generation (3G), 4thGeneration (4G), Wideband Code Division Multiple Access (WCDMA), andGlobal System for Mobile communications (GSM), but an exemplaryembodiment is not limited to a specific one.

Hereinafter, configurations of a system and a portable terminal andoperation control methods thereof according to an exemplary embodimentwill be described with reference to the accompanying drawings. Since theconfigurations of a system and a portable terminal and operation controlmethods thereof according to an exemplary embodiment are not limited tofollowing embodiments, various embodiment are applicable based onfollowing embodiments.

FIG. 1 is a schematic diagram illustrating a configuration of a systemfor describing an operation of establishing a WLAN link between portableterminals according to an exemplary embodiment.

As shown in FIG. 1, the system 98 includes a first portable terminal100, a contact server 200, and one or more second portable terminals300, for example, a portable terminal 310, a portable terminal 320, anda portable terminal 330. An exemplary embodiment illustrates anoperation of establishing a WLAN link with at least one of the secondportable terminals 300 by the first portable terminal 100. Establishingthe WLAN link between two potable terminals means that the two portableterminals are connected to communicate with each other through the WLAN500.

In an exemplary embodiment, the first portable terminal 100 may operateas an access point (AP), and the second portable terminals 300, forexample, the portable terminal 310, the portable terminal 320, and theportable terminal 330 may operate as a Non-AP station. Although FIG. 1shows three Non-AP stations such as the portable terminal 310, theportable terminal 320, and the portable terminal 330, it is apparent toa person having ordinary skill in the art that one or more Non-APstations may be included.

The first portable terminal 100 may have a security key (hereinafterreferred to as ‘first security key’ or ‘source security key’) forauthenticating other party portable terminal for WLAN connection, and atleast two partial security keys divided from the first security key.That is, the first portable terminal 100 may divide a first one securitykey into two or more partial security keys according to user setting (orinput). The first portable terminal 100 may transmit a part of at leasttwo partial security keys to the second portable terminal 300 throughthe cellular network, and transmit a remaining of the partial securitykeys to the portable terminal 300 through a sound in order to reinforcesecurity stability of a security key for establishing the WLAN link. Theuser previously has the first security key and the partial security keysor the first security key and the partial security keys may be generatedevery WLAN connection operation.

The portable terminal 100 may request contact information to the contactserver 200 in response to a user request, and receive contactinformation provided from the contact server 200 to display a contactlist. The contact information refers to user information of usersregistered in the contact server 200 by a user of the first portableterminal 100 or user information of users associated with the user ofthe first portable terminal 100 collected based on an SNS by the contactserver 200, and may be implemented in various forms such as a phonenumber, a name, a nick name, and identification (ID). Particularly, inan exemplary embodiment, the contact list may include contactinformation of a user located at a neighboring zone of the user of thefirst portable 100. For example, the contact list may include a list ofusers present at the same zone (e.g., zone in coverage of a base stationto which the first portable terminal 100 belongs) as that of the user ofthe first portable terminal 100 among users having specific relationship(relationship according to user setting of the first portable terminal100 such as e.g., friends, acquaintances, family, colleagues).

If at least one contact information item is selected from the contactlist, the first portable terminal 100 transmits a connection requestmessage requesting WLAN connection with at least one second portableterminal 300 corresponding to at least one selected contact informationitem to the contact server 200 through the cellular network 400. Thefirst portable terminal 100 may transmit the connection request messageincluding one (hereinafter referred to as ‘first partial security key’)of the partial security keys and connection information, for WLANconnection. The first portable terminal 100 may load a remaining partialsecurity key (hereinafter referred to as ‘second partial security key’)in a sound (e.g., sound wave, ultrasonic wave) and outputs the loadedsound through a speaker. The first portable terminal 100 may control theoutput of the sound according to an output level of a speaker by usersetting.

The output level of the speaker may be determined according to a soundreach distance (or reach range) by the user setting. That is, the outputlevel of the speaker may be provided by setting a reachable distance ofthe sound other than inputting the output level of the speaker. Forexample, the reachable distance of the sound may be variously setaccording to user setting, that is, 5 m, 25 m, 50 m, and 100 m. Thefirst portable terminal 100 may determine the output level of thespeaker according to the set reachable distance, and output the soundbased on the determined output level of the speaker.

For example, an output level with respect to a reach distance of 5 m maybe set to “A”, an output level with respect to a reach distance of 25 mmay be set to “B”, an output level with respect to a reach distance of50 m may be set to “C”, and an output level with respect to a reachdistance of 100 m may be set to “D”. The output levels “A”, “B”, “C”,and “D” determine an output level of a speaker of the portable terminal.As the reach distance is lengthened, magnitude of the output level maybe increased. That is, for example, the output levels “A”, “B”, “C”, and“D” may be defined in the order of “A<B<C<D”.

When receiving a WLAN connection request from at least one secondportable terminal 300, the first portable terminal 100 may confirm asecurity key (hereinafter referred to as ‘second security key’ or‘combination security key’) from the second portable terminal 300according to the WLAN connection request. That is, the second securitykey indicates a security key which is a combination of a first partialsecurity key acquired through a cellular network by the second portableterminal 300 and a second partial security key acquired through thesound by the second portable terminal 300. The first portable terminal100 may compare the second received security key with the first securitykey. The first portable terminal 100 may authenticate the secondportable terminal 300 through comparison of the first security key andthe second security key, and establish the WLAN link based on theauthentication result.

When receiving a contact information request from the first portableterminal 100, the contact server 200 may identify the first portableterminal 100, and may collect contact information associated with thefirst portable terminal 100. For example, the contact server 200 maycollect user information of users which a user of the first portableterminal 100 registers in the contact server 200 to acquire the contactinformation. The contact server 200 may collect user information ofusers related to the user of the first portable terminal 100 based on anSNS to acquire the contact information. The contact server 200 maytransmit the contact information to the first portable terminal 100 inresponse to a request from the first portable terminal 100.Particularly, the contact server 200 may configure the contactinformation based on a location of the first portable terminal 100 amonguser information of all users specifically related to the user of thefirst portable terminal 100. That is, the contact server 200 may searchthe second portable terminal 300 located at the same zone (e.g., a zonein coverage of a base station to which the first portable terminal 100belongs) as that of the first portable terminal 100 to configure thecontact information. Accordingly, the contact server 200 may classifylocations of respective portable terminals in units of networks(particularly, units of base stations) connected with a network. Thecontact server 200 may classify locations of the respective portableterminals using a location based service (e.g., friend finder service).The locations of the portable terminals may be classified by variousmechanisms.

When receiving a connection request message requesting the WLANconnection with at least one second portable terminal 300 from the firstportable terminal 100, the contact server 200 may transmit theconnection request message to the at least one second portable terminal300 through a cellular network 400. As described above, the connectionrequest message includes connection information and a partial securitykey, and may be pushed to the at least one second portable terminal 300in the push mechanism by the contact server 200. The push mechanism isgenerally known in a communication field, and thus a detaileddescription thereof is omitted.

The contact server 200 is specified as one server in an exemplaryembodiment, but the contact server 200 may separately include a pushserver (not shown). For example, when receiving the connection requestmessage from the first portable terminal 100, the contact server 200 maytransfer the connection request message to the push server to request atleast one second portable terminal 200 to push. Then, the push servermay transmit the connection request message to the at least one secondportable terminal 300 in a push mechanism.

When receiving the connection request message from the contact server200 in the push mechanism, the second portable terminal 300 may acquireinformation of the first portable terminal 100 from connectioninformation included in the connection request message, and may providefeedback to the respective user that a WLAN connection request isreceived from the first portable terminal 100. If the WLAN connectionrequest is approved by the user, the second portable terminal 300 mayturn-on a microphone in response to the connection request message, andmay wait for reception of a sound provided from the first portableterminal 100. The second portable terminal 300 may acquire and store afirst partial security key included in the connection request message.

If the sound output from the first portable terminal 100 is inputthrough a microphone, the second portable terminal 300 may acquire asecond partial security key included in the sound, and combine thesecond partial security key with the first partial security key togenerate a second security key. The second portable terminal 300 maytransmit a WLAN connection request using the second security key to thefirst portable terminal 100 through a WLAN 500, and may establish a WLANlink with the first portable terminal 100 according to a response of thefirst portable terminal 100.

The foregoing exemplary embodiment illustrates the first portableterminal 100, the contact server 200, and the second portable terminalconstituting the system 98 according to an exemplary embodiment withreference to FIG. 1. Hereinafter, a method of establishing a WLAN linkaccording to an exemplary embodiment will be described.

As shown in FIG. 1, the user may execute an application (hereinafterreferred to as ‘connection application’) for establishing the WLAN linkin the first portable terminal 100. Then, the first portable terminal100 executes the connection application and request contact informationto the contact server 200 through a cellular network 400 (operation101).

The contact information refers to user information of users registeredin the contact server 200 by a user of the first portable terminal 100through the connection application or user information of usersassociated with the user of the first portable terminal 100 collectedbased on an SNS by the contact server 200, and may be implemented invarious forms such as a phone number, a name, a nick name, and ID. Theconnection application may be a dedicated application for performingonly a procedure of establishing a WLAN link according to an exemplaryembodiment, and an application providing various services. For example,the connection application may be an application providing a mobilemessenger service, an SNS, and a service playing multi-media contents.

When receiving a contents information request from the first portableterminal 100, the contact server 200 collects one or more contactinformation associated with the user of the first portable terminal 100,and transmits the collected contact information to the first portableterminal 100 (operation 103).

When receiving the contact information from the contact server 200, thefirst portable terminal 100 generates and displays a contact list basedon the contact information so that the user may select at least onecontact information item from the contact list. For example, the usermay select contact information of the second portable terminal 300 suchas at least one of the portable terminal 310, the portable terminal 320,and the portable terminal 330 from the contact list. Then, the firstportable terminal 100 transmits a connection request message to thecontact server 200 through a cellular network 400 in order to establisha WLAN link with the second portable terminal 300 (operation 105). Thefirst portable terminal 100 may transmit the connection request messageincluding connection information and first partial security key. Theconnection information may include information to establish the WLANlink with the first portable terminal 100, for example, a Service SetIdentifier (SSID) of the WLAN 500, a channel number, other securityinformation, and contact information according to user selection.

The WLAN link may include a WLAN connection mode such as an ad hoc modeand an infrastructure mode. That is, a selection menu for selecting oneWLAN connection mode from the ad hoc mode and the infrastructure modemay be displayed on a screen of the first portable terminal so that theuser may select one from the ad hoc mode and the infrastructure modethrough the selection menu. The WLAN connection mode may beautomatically determined according to a type of application. Forexample, when the application streams the music from the first portableterminal 100 to the second portable terminal 300 such as the portableterminal 310, the portable terminal 320, and the portable terminal 330,the infrastructure mode may be automatically selected. If the firstportable terminal 100 and the second portable terminal 300 transmittheir camera view (e.g., a photographed screen is displayed) to eachother, the ad hoc mode may be automatically selected.

The ad hoc mode and the infrastructure mode with respect to the type ofapplication may be selected by the user. The ad hoc mode or theinfrastructure mode may be selected by the number of other portableterminals which may be connected to the first portable terminal 100. Forexample, when the first terminal 100 requests connection to a pluralityof other portable terminals, the infrastructure mode may be selected.When the first portable terminal 100 requests connection to anotherportable terminal, the ad hoc mode may be selected. The ad hoc mode andthe infrastructure mode may be selected in the first portable terminal100 by various methods.

If the WLAN connection mode is selected by one of the foregoingmechanisms, the first portable terminal 100 may execute a function as anAP, and the connection information of the connection request message mayinclude mode information indicating whether to establish the WLAN linkin the ad hoc mode or the infrastructure mode. The connection requestmessage of an exemplary embodiment will be described in detail withreference to FIG. 2 below.

The user for the first portable terminal 100 may not only establish theWLAN link but also execute a specific connection application in thesecond portable terminal 300.

For example, when the connection application currently executed in thefirst portable terminal 100 is a chatting application providing achatting service, the user of the first portable terminal 100 mayexecute the same chatting application in the second portable terminal300 to enjoy a chatting service with the user of the second portableterminal 300 through the WLAN 500. The user of the first portableterminal 100 may wish to execute a music playback application of thesecond portable terminal 300 to play a music file stored in the firstportable terminal 100 in the second portable terminal 300 through theWLAN 500 in a streaming operation. The connection information of theconnection request message may include an ID indicating a specificconnection application. The ID may be mapped to the same connectionapplication by the first portable terminal 100 and the second portableterminal 300, and may be generated from the first portable terminal 100or be extracted from a corresponding connection application.

Referring back to FIG. 1, when receiving a connecting request messagefrom the first portable terminal 100, the contact server 200 transmitsthe connection request message to at least one second portable terminal300 in a push mechanism (operation 107). The system 98 may include apush server (not shown) implemented separately or within the contactserver 200. The contact server 200 may transfer the connection requestmessage to the push server (not shown), and request the push server totransmit the connection request message to the second portable terminal300 in the push mechanism. Then, the push server (not shown) may pushthe connection request message to the second portable terminal 300through the cellular network 400.

When receiving the connection request message, the second portableterminal 300 may display a selection menu confirming whether toestablish the WLAN link with the first portable terminal 100, that is,whether to connect with the first portable terminal 100 through the WLAN500, on a screen. The user of the second portable terminal 300 approvesconnection through the selection menu, the second portable terminal 300turns-on a microphone and waits for reception of a sound output from thefirst portable terminal 100 (operation 109). The second portableterminal 300 may acquire and manage a first partial security keyincluded in the connection request message.

The first portable terminal 100 transmits the connection requestmessage, loads a second partial security in the sound, and outputs theloaded sound through the speaker (operation 111). The first portableterminal may output a sound according to a preset output level (e.g.,output intensity according to a reach distance of the sound) of thespeaker.

When the sound output from the first portable terminal 100 through theturned-on microphone is input, the second portable terminal 300 acquiresa second partial security key included in the sound, and combines thesecond partial security key with the first partial security key togenerate a second security key. The second portable terminal 300 requestWLAN connection to the first portable terminal 100 through a WLANinterface using the used connection information of the connectionrequest message and the second security key (operation 113).

The second portable terminal 300 may request the WLAN connection to thefirst portable terminal 100 using one of a cellular network and a WLAN.When a WLAN function is turned-off, the second portable terminal 300 mayactivate the WLAN function when an input approving connection throughthe selection menu is received or the sound is received through themicrophone. In addition, the second portable terminal 300 may extract aconnection application ID from the connection information of theconnection request message, and may search and execute a connectionapplication indicated by the connection application ID. That is,according to an exemplary embodiment, when the connection application IDis included in the connection information, the portable terminal forsupporting a function establishing a WLAN link may execute acorresponding connection application. Accordingly, the second portableterminal 300 may receive contents from the first portable terminal 100through the connection application. For example, when the connectionapplication ID is included in the received connection information, thesecond portable terminal 100 may execute a music playback applicationindicated by the connection application ID to play a music file streamedby the first portable terminal 100.

Referring back to FIG. 1, when receiving a WLAN connection request fromthe second portable terminal 300 through the WLAN 500 based on thesecond security key, the first portable terminal 100 may compare thesecond security key with a first security key which the first portableterminal 100 has, and may authenticate the second portable terminal 300requesting the establishment of the WLAN link (operation 115). The firstportable terminal 100 may establish the WLAN link with the secondportable terminal 300 having transmitted a corresponding second securitykey, and may transmit data according to a user request through the WLAN500.

As described above, according to an exemplary embodiment, the user ofthe first portable terminal 100 may establish the WLAN link without acomplicated setting procedure only by selecting contact information froma user-friendly contact list. The user of the second portable terminal300 may establish the WLAN link without the complicated settingprocedure by only an operation of pushing a connection request button ina selection menu displayed on a screen according to the connectionrequest message. According to an exemplary embodiment, with respect tothe security key for establishing the WLAN link, a first one securitykey is divided into a first partial security key and a second partialsecurity key, and the first partial security key and a second partialsecurity key are provided separately through the cellular network andthe sound so that security stability may be reinforced.

FIG. 2 is a schematic diagram illustrating an example of a connectionrequest message format according to an exemplary embodiment.

Referring to FIG. 2, the connection request message includes an SSIDfield 201, a channel number field 202, a security mechanism field 203, asecurity key field 204, a connection mode field 205, and an applicationidentifier (ID) field 206. Under this arrangement, as described above,the connection information (e.g., SSID, channel number, other securityinformation, application ID, and contact information according to userselection) and a partial security key may be provided. As describedabove, the connection request message is transmitted to the secondportable terminal 300 through the cellular network 400 by the firstportable terminal 100, and is used to establish a WLAN link between thefirst portable terminal 100 and the second portable terminal 300.

The SSID field 201 indicates an SSID of a WLAN 400 to which the firstportable terminal 100 belongs.

The channel number field 202 indicates through which wireless channelthe second portable terminal 300 establishes a WLAN link with the firstportable terminal 100 in the WLAN 400 designated by the SSID field 210.

The security mechanism field 203 indicates a security mechanism to beapplied to the WLAN link between the first portable terminal 100 and thesecond portable terminal 300. For example, the security mechanism fieldmay designate a security mechanism such as Wired Equivalent Privacy(WEP), Wi-Fi Protected Access (WPA), and Wi-Fi Protected Access2 (WPA2),and may designate an open scheme which does not use a separate securitymechanism.

A security key for ensuring security stability in a WLAN link betweenthe first portable terminal 100 and the second portable terminal 300 isrecorded in the security key field 204. Particularly, a partial securitykey divided from the first security key of the first portable terminal100 is recorded in the security key field 204, and the first portableterminal 100 authenticates the second portable terminal 300 using asecurity key which is a combination of the partial security key andanother partial security key transmitted through the sound.

The connection mode field 205 contains information indicating throughwhich mechanism the first portable terminal 100 and the second portableterminal 300 establish the WLAN link. As described above, the modeinformation may indicate an infrastructure mode or an ad hoc mode.

An application ID indicating which connection application is executedafter the second portable terminal 300 receives the connection requestmessage is recorded in the application ID field 206. The application IDfield 206 may include metadata of contents which the first portableterminal 100 transmits to the second portable terminal 300 through acorresponding connection application except for a connection applicationwhich the second portable terminal 300 will execute. A title, a singername, and a music playback time of a music file which the first portableterminal 100 will stream to the second portable terminal 300 may berecorded in the application ID field 206.

If the connection request message is received, the second portableterminal 300 executes a specific connection application with referenceto the application ID field 206, and performs data communication withthe first portable terminal 100 through the connection application. Forexample, the second portable terminal 300 may execute a music playbackapplication with reference to the application ID field 206 included in aconnection request message, and may play a music streamed through theWLAN link from the first portable terminal 100.

Respective fields of the connection request message may be transmittedat different times through a separate message. For example, after theapplication ID and metadata of contents are transmitted to the secondportable terminal 300, if the user of the second portable terminal 300approves connection through the WLAN 500, remaining information may betransmitted to the second portable terminal 300. After establishment ofthe WLAN link is terminated, the application ID or contents metadatarecorded in the application ID field 206 may be transmitted to thesecond portable terminal 300.

Since a format of the connection request message shown in FIG. 2 is oneexample, a part of fields 201 to 206 shown in FIG. 2 may be omittedaccording to an implementation, and a new field which is not shown inFIG. 2 may be added. For example, the format of the connection requestmessage may include a message type field indicating a type of connectionrequest message and a contact information field indicating desiredcontact information of a portable terminal. Lengths of fields in unitsof octets shown in FIG. 2 may be changed.

FIG. 3 is a block diagram schematically illustrating a configuration ofa portable terminal 306 according to an exemplary embodiment. Theportable terminal 306 may represent the first portable terminal 100and/or the second portable terminal 300, and a configuration of FIG. 3may be implemented in both of the first portable terminal 100 and thesecond portable terminal 300.

Referring to FIG. 3, the portable terminal 306 includes a radiofrequency (RF) communication unit 308, a user input unit 318, a display328, an audio processor 340, a memory 350, an interface 360, acontroller 370, and a power supply 380. The portable terminal mayinclude more or fewer elements than those shown in FIG. 3.

The RF communication unit 308 may include at least one module whichenables wireless communication between the portable terminal and awireless communication system or between the portable terminal and anetwork in which the portable terminal is located. For example, the RFcommunication unit 308 may include a mobile communication module 311, aWLAN module 313, a near field communication module 315, a locationcomputing module 317, and a broadcast receiving module 319.

The mobile communication module 311 transceives a wireless signal withat least one of a base station, an external terminal, and a server overa mobile communication network. The wireless signal may include a voicecall signal, an image call signal or data of various formats accordingto transceiving of character/multi-media message. Particularly, themobile communication module 311 may transmit and receive a partialsecurity key through the cellular network.

The WLAN module 313 is a module to connect with a wireless Internet andestablish a WLAN link with another portable terminal, and may beinstalled inside or outside the portable terminal. WLAN (Wi-Fi),Wireless broadband (Wibro), World Interoperability for Microwave Access(Wimax), High Speed Downlink Packet Access (HSDPA) may be used as awireless Internet technology. Particularly, the WLAN module 313 performscommunication associated with an operation of establishing the WLANlink.

The near field communication module 315 is a module for near fieldcommunication. Bluetooth, Radio Frequency ID (RFID), infrared DataAssociation (IrDA), Ultra Wideband (UWB), ZigBee, or Near FieldCommunication (NFC) may be used as a short range communicationtechnology.

The location computing module 315 is a module for acquiring a locationof the portable terminal. A Global Position System (GPS) is arepresentative example of the location computing module 315. Thelocation computing module 315 computes distance information from atleast three base stations and exact time information, appliestriangulation to the computed distance and time information to computethree dimensional current location information according to thelatitude, the longitude, and the height. The location computing module315 may continuously receive a current location of the portable terminalfrom at least three satellites to compute location information. Thelocation information of the portable terminal may be acquired by variousmethods.

The broadcast receiving module 319 receives a broadcast signal (e.g., TVbroadcast signal, radio broadcast signal, data broadcast signal) and/orinformation (e.g., a broadcast channel, information associated with abroadcast program or a broadcast service provider) associated with thebroadcasting from an external broadcast management server through abroadcast channel (e.g., satellite channel, terrestrial channel).Particularly, a digital broadcast signal received through the broadcastreceiving module 319 of the first portable terminal 100 may bebroadcasted to the second portable terminal 300.

The user input unit 318 allows the user to generate input data forcontrolling an operation of the portable terminal. The user input unit318 may be a key pad, a dome switch, a touch pad (constantpressure/capacitive), a jog wheel, or a jog switch.

The display 328 displays (outputs) information processed by the portableterminal. For example, when the portable terminal is in a call mode, thedisplay 328 displays User Interface (UI) or Graphical UI (GUI). When theportable terminal is in an image call mode or a shooting mode, thedisplay 328 displays a shot, a received image, a UI, and/or a GUI.Particularly, the display 328 displays UI or GUI associated with anoperation of establishing the WLAN link. A screen arrangement of thedisplay 328 and an example of a screen thereof according to an exemplaryembodiment will be described below.

The display 328 may include at least one of a liquid crystal display(LCD), a thin film transistor-liquid crystal display (TFT LCD), a LightEmitting Diode (LED), an organic LED (OLED), an Active Matrix OLED(AMOLED), a flexible display, a bended display, and a 3D display. Someof the above displays may be configured in a transparent type or a lighttransmittance type to look out the outside therethrough.

According to an exemplary embodiment, when a touch panel (hereinafter,referred to as ‘touch screen’ for sensing a touch operation and thedisplay 328 are constructed in a layer structure, the display may beused as the input unit as well as the output unit.

The touch panel may be configured to convert a pressure applied to aspecific portion of the display or a variation of capacitance generatedfrom the specific portion of the display 328 into an electrical inputsignal. The touch panel may be configured to detect a pressure whentouching the display as well as the touched location and area.

When the touch input is generated with respect to the touch panel, thesignal corresponding to the touch input is transferred to a touchcontroller. The touch controller processes the signal and transfers datacorresponding to the signal to the controller 370. Thus, the controller370 may recognize which area is touched in the display 328.

The audio processor 340 transmits an audio signal from the controller370 to the speaker 341. The audio processor 340 transfers an audiosignal such as a voice from the microphone 343 to the controller 370.The audio processor 340 converts voice/sound data into an audible soundthrough the speaker 341 under the control of the controller 370 andoutputs the audible sound. The audio processor 340 may convert an audiosignal such as a voice from the microphone 343 into a digital signal andtransfer the digital signal to the controller 370. Particularly, theaudio processor 340 according outputs a sound including a partialsecurity key through the speaker 341 under the control of the controller370. Upon output of a sound including the partial security key throughthe speaker 341, the audio processor 340 processes output to correspondto an output level of the speaker set under the control of thecontroller 370. At least one of the audio processor 340 and the speaker341 may include an additional circuit and electronic component (e.g.,resistor, capacitor) so that the sound is input to another portableterminal located at a neighboring region, through a microphone of theanother portable terminal.

The speaker 341 may receive audio data from the RF communication unit308 or output audio data stored in the memory 350 in a call mode, arecord mode, a voice recognition mode, and a broadcast receiving mode.The speaker 341 may output a sound signal associated with a function(e.g., a call signal receiving sound, a message receiving sound, a musicfile playback) executed by the portable terminal. Particularly, thespeaker 341 output a sound into which the partial security key is loadedaccording a preset output level.

The microphone receives an external sound signal and processes it aselectric voice data is in a call mode, a record mode, and a voicerecognition mode. When the portable terminal in the call mode, theprocessed voice data are converted into a transmittable form through themobile communication module 311 and output to a mobile communicationbase station. Various noise removal algorithms for removing a noiseoccurring during a procedure of receiving an external sound signal maybe implemented in the microphone 343. For example, the microphone 343may receive a sound from a speaker of another portable terminal andtransfer the received sound to the controller 370.

The memory 350 may store a program for operating the control unit 370and may temporarily store input/output data (for example, a phone book,a message, audio, a still image, electronic book, a moving image, asound, partial security key). The memory 350 may store data aboutvibrations and audio of various patterns output when a touch inputoccurs on the touch screen. Particularly, the memory 350 may store afirst security key, a first partial security key acquired from aconnection request message received through a cellular network 400, anda second partial security key acquired from a sound received from amicrophone.

The memory 350 may include a storage medium having at least one type ofa flash memory type, a hard disk type, a micro type, a card type of amemory (for example, an SD or XD memory), RAM (Random Access Memory),SRAM (Static Random Access Memory), ROM (Read-Only Memory), EEPROM(Electrically Erasable Programmable Read-Only Memory), PROM(Programmable Read-Only Memory), MRAM (Magnetic RAM), a magnetic disc,and an optical disc. The portable terminal may operate associated with aweb storage executing a storage function of the memory 350 in anInternet.

The interface 360 serves as a path to connect various external devicesto the portable terminal. The interface 360 may receive data or powerfrom an external device, transfer the data or power to each element inthe portable terminal, or transmit data of the voice recognitionfunction to an external device. For example, the interface 360 mayinclude a wired/wireless headset port, an external charger port, awired/wireless data port, a memory card port, a port of connecting adevice having an identity module, an audio input/output (I/O) port, avideo I/O port and an earphone port.

The controller 370 controls an overall operation of the portableterminal. For example, the controller 370 performs control andprocessing associated with a voice call, data communication, and animage call. The controller 370 may include a multi-media module forplaying multi-media. The multi-media module may be implemented inside orseparately from the controller 370. Particularly, the controller 370performs overall control for an operation establishing a WLAN link. Uponestablishment of a WLAN link, the controller 370 may control anoperation of a transmitter portable terminal (e.g., first portableterminal 100) starting a service. Upon reception of the connectionrequest message, the controller 370 may turn-on the microphone 343 tocontrol an operation of a receiver portable terminal (e.g., secondportable terminal 300) receiving a sound of the transmitter portableterminal.

First, a case where the portable terminal operates as the transmitterportable terminal is described.

If the user executes a connection application, the controller 370acquires contact information from the contact server 200, and controlsdisplay of a contact list based on the acquired contact information.When the contact information is selected from the contact list, thecontroller 370 may generate and transmit a connection request messageincluding connection information and a part of a first partial securitykey divided from the first security key to the contact server 200. Aftertransmitting the connection request message, the controller 370 loads aremaining part of the first security key, i.e., a second partialsecurity key, divided from the first security key into a sound, andoutputs the loaded sound through the speaker 341. The controller 370 maycontrol output of the sound based on a preset output level.

Upon reception of a WLAN connection request including the secondsecurity key from one or more receiver portable terminals after theoutput of the sound, the controller 370 compares the second security keywith the first security key to authenticate the receiver portableterminal.

Next, a case where the portable terminal operates as the receiverportable terminal will be described.

If the connection request message is pushed from the contact server, thecontroller 370 may control display a selection menu to confirm whetherto establish a WLAN link with the transmitter portable terminal throughthe display 328. If the user approves connection through the selectionmenu, the controller 370 may control turning-on of the microphone 343.The controller 370 may extract and manage a first partial security keyfrom the connection request message.

When the sound output from another portable terminal is input throughthe turned-on microphone, the controller 370 may extract the secondpartial security key from the input sound. The controller 370 maycombine the second partial security key acquired from the sound with thefirst partial security key acquired from the connection request messageto generate a second security key. The controller 370 requests WLANconnection to the transmitter portable terminal using the connectioninformation and the second security key of the connection requestmessage, and controls a procedure of establishing a corresponding WLANlink. When a WLAN function is turned-off, the controller 370 mayactivate the WLAN function when an input approving connection throughthe selection menu is received or a sound is received through themicrophone 343.

The power supply 380 uses power which is applied from an external powersource or an internal power source and supplies the power to operateeach constituent element to each constituent element, under control ofthe controller 370.

Exemplary embodiments may be implemented in a recording medium capableof being read by a computer or a similar device using software,hardware, and a combination thereof. According to hardwareimplementation, exemplary embodiments may be realized using at least oneof Application Specific Integrated Circuits (ASICs), digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, micro-controllers, microprocessors,and an electric unit for performing other functions. In some cases,exemplary embodiments described in the specification may be implementedby the controller 370. According to software implementation, exemplaryembodiments such as procedures and functions described in thespecification may be realized by separate software modules. Each of thesoftware modules may perform at least one function and operationdescribed in the specification.

The portable terminal shown in FIG. 3 may include various devices usingApplication Processor (AP), Graphic Processing Unit (GPU), and CentralProcessing Unit (CPU) such as various information communication device,multi-media devices, and application devices thereof supportingexemplary embodiments. For example, the network electronic deviceincludes electronic devices such as PC, Smart Phone, digital camera,Portable Multimedia Player (PMP), media player, portable game terminal,laptop computer, and PDA as well as mobile communication terminalsoperating based on respective communication protocols corresponding tovarious communication systems. In addition, a control method of anexemplary embodiment may be applied to various display devices such asDigital Television (DTV), Digital Signage (DS), and Large Format Display(LFD).

FIG. 4 is a signal flow chart illustrating a method of establishing aWLAN link between a first portable terminal 100 and a second portableterminal 300 according to an exemplary embodiment.

Referring to FIG. 4, a first portable terminal 100 executes a connectionapplication in response to a user request (operation 401), and requestscontact information from a contact server 200 through a cellular network400 (operation 403).

Upon reception of a request of the contact information from the firstportable terminal 100, the contact server 200 may identify the firstportable terminal 100 (operation 405), and collect contact informationrelated to a user of the first portable terminal 100 (operation 407).The contact information may be user information which the user of thefirst portable terminal 100 registers in the contact server 200 or userinformation related to the user of the first portable terminal 100collected by the contact server 200 based on an SNS. The contact server200 may transmit the collected contact information to the first portableterminal 100 (operation 409).

Upon reception of the contact information from the contact server 200,the first portable terminal 100 displays a contact list based on thereceived contact information (operation 411), and receives selection ofat least one contact information item from the contact list (operation413). If the contact information is selected, the first portableterminal 100 may transmit a connection request message for establishinga WLAN link to a contact server 200 through a cellular network 400(operation 415). If the contact information is selected from the user,the first portable terminal 100 may divide a first security key storedor newly generated into a first partial security key and a secondpartial security key. The first portable terminal 100 may transmit theconnection request message including connection information forestablishing the WLAN link and a part (e.g., first partial security key)of at least two partial security keys divided from the first securitykey.

When receiving the connection request message from the first portableterminal 100, the contact server 200 may transmit the receivedconnection request message to at least one second portable terminal 300,for example, portable terminal 310 and portable terminal 320, in a pushmechanism (operation 417). The contact server 200 identifies a firstportable terminal 100 having transmitted the connection request message,and parses a message from the first portable terminal 100 to confirm atype of the received message. The type of the received message may beconfirmed from message type information in the received message. Whenthe type of the received message corresponds to the connection requestmessage for establishing a WLAN link with the second portable terminal300, the contact server 200 may identify the second portable terminal300 based on the contact information included in the connection requestmessage. FIG. 4 illustrates a case where the portable terminal 310 andthe portable terminal 320 are identified by way of example. Accordingly,the contact server 200 may push the connection request message to theidentified portable terminal 310 and portable terminal 320.

When receiving the connection request message from the contact server200, the portable terminal 310 and the portable terminal 320 may displaya selection menu for confirming whether to establish the WLAN link withthe first portable terminal 100, respectively (operations 419 and 425).If the user approves connection through the selection menu, the portableterminal 310 and the portable terminal 320 may turn-on a microphone 343,respectively (operations 421 and 427). Upon reception of the messagefrom the contact server 200, the portable terminal 310 and the portableterminal 320 may confirm a type of the received message through messageparsing. The type of the received message may be confirmed from messagetype information included in the message. When the type of the receivedmessage corresponds to the connection request message for establishingthe WLAN link, the portable terminal 310 and the portable terminal 320may turn-on the microphone 343 and wait for reception of the sound inresponse to the connection request message. Upon reception of theconnection request message, the portable terminal 310 and the portableterminal 320 may extract and manage connection information and a partialsecurity key (first partial security key) included in the connectionrequest message (operations 423 and 429).

The first portable terminal 100 may transmit the connection requestmessage and output a sound including a remaining partial security key(second partial security key) of the at least two partial security keysdivided from the first security key after a predetermined time throughthe speaker 341 (operation 431). The predetermined time may be variouslydefined as 5 seconds, 10 seconds, 15 seconds, and 30 seconds accordingto user setting. The first portable terminal 100 may output a sound withthe second partial security key according to an output level of thespeaker 341 corresponding to a preset reach time.

For example, the sound output from the first portable terminal 100reaches the portable terminal 310, and does not reach the portableterminal 320. That is, it is assumed that the portable terminal 310 islocated within a sound reach range and the portable terminal 320 islocated beyond the sound reach range based on a location of the firstportable terminal 100. Accordingly, the sound including the secondpartial security key output from the first portable terminal 100 isinput to only the portable terminal 310 through the microphone 343, butis not input to the portable terminal 320.

When the sound including the second partial security key from the firstportable terminal 100 is not input until a predetermined time elapsesafter turning on of the microphone 343, the portable terminal 320 mayturn-off the microphone 343 (operation 433). If a sound without thesecond partial security key is received from another portable terminalin a state that the microphone 343 is turned-on, the portable terminal320 may disregard a corresponding sound and turn-off the microphone 343after a predetermined time (e.g., 30 second, 1 minutes, 5 minutes)elapses. If the sound is input through the microphone 343, the portableterminal 310 may acquire the second partial security key loaded in thesound (operation 435). When acquiring the second partial security key,the portable terminal 310 combines the second partial security keyacquired through the sound with the first partial security key acquiredthrough the connection request message (operation 437) to generate onesecurity key (operation 439). The portable terminal 310 may request aWLAN connection to the first portable terminal 100 using the connectioninformation and the second security key of the connection requestmessage (operation 441).

Upon reception of the WLAN connection request from the portable terminal310, the first portable terminal 100 may authenticate the portableterminal 310 (operation 443). The first portable terminal 100 maycompare the second received security key with the first security keyincluded in the first portable terminal 100 to authenticate the portableterminal 310 according to presence of correspondence thereof.

When the second security key corresponds to the first security key, theportable terminal 100 may establish the WLAN link with the portableterminal 310 (operation 445). For example, the first portable terminal100 may transmit a response accepting establishment of the WLAN link tothe portable terminal 310 to establish the WLAN link in response to arequest of establishment of the WLAN link of the portable terminal 310.

In the foregoing exemplary embodiment, the first portable terminal 100acquires the contact information from the contact server 200 inoperations 403 to 409, but procedures of requesting and receiving thecontact information of operations 403 to 409 may be omitted. Forexample, upon execution of a connection application (operation 401), thefirst portable terminal 100 displays a contact list (operation 411)based on stored contact information and performs remaining operations413 to 445.

FIG. 5 is a flow chart illustrating a control method when a portableterminal operates as a transmitter portable terminal according to anexemplary embodiment.

A transmitter portable terminal (e.g., first portable terminal 100)initiates a procedure of establishing a WLAN link with a receiverportable terminal (e.g., second portable terminal 300). That is, thetransmitter portable terminal performs a function of the first portableterminal 100 and the receiver portable terminal performs a function ofthe second portable terminal 300, as described above with reference toFIGS. 1 to 4. The second portable terminal 300 may be one of a portableterminal 310, a portable terminal 320, and a portable terminal 330, ormay include at least two of the portable terminal 310, the portableterminal 320, and the portable terminal 330.

Referring to FIG. 5, the controller 370 executes a connectionapplication according to user input (operation 501). Upon the executionof the connection application, the controller 370 divides one firstsecurity key into a first partial security key and a second partialsecurity key (operation 503). The first security key, the first partialsecurity key, and the second partial security key may be previouslystored. As described above, upon the execution of the connectionapplication, the first partial security key and the second partialsecurity key may be configured by the second security key or a newsecurity key.

As the connection application is executed, the controller 370 acquirescontact information from the contact server 200 through a cellularnetwork 400 (operation 505). The controller 370 displays a contact listbased on the acquired contact information on a screen (operation 507).

If user selection with respect to at least one contact information itemfrom the contact list is input (operation 509), the controller 370transmits a connection request message to the contact server 200(operation 511). The user may select at least one contact informationfrom the contact list using a user input unit 318. When the at least onecontact information is selected, the controller 370 may generate theconnection request message including a first partial security key amongpartial security keys divided from the first security key and connectioninformation for the WLAN connection and transmit the connection requestmessage to the contact server 200.

The controller 370 controls output of a sound into which the partialsecurity key is loaded after transmission of the connection requestmessage (operation 513). The controller 370 may output a sound in whicha second partial security key among partial security keys divided fromthe first security key is loaded according a preset output level. Thecontroller 370 may wait for a preset appointed time after transmissionof the connection request message and then output the sound, and mayperiodically output the sound according to a preset period when theconnection request message is transmitted.

When receiving a request of WLAN connection from the at least one secondportable terminal 300 (operation 515), the controller 370 authenticatesa second portable terminal 300 having requested the WLAN connection(operation 517). The controller 370 acquires a second security keyprovided from the second portable terminal 300 together with the requestof the WLAN connection, and may authenticate the second portableterminal 300 by comparing the second security key with the firstsecurity key.

When the authentication with respect to the second portable terminal 300is normally completed, that is, when the second security key correspondsto the first security key, the controller 370 establishes the WLAN linkwith the second portable terminal 300 (operation 519). That is, thesecond portable terminal 300 may request the WLAN connection to thefirst portable terminal 100 using a second security key being acombination of a first partial security key acquired from the connectionrequest message and a second partial security key acquired from thesound, and connection information acquired from the connection requestmessage. Then, the first portable terminal 100 may authenticate thesecond portable terminal 300, and may establish the WLAN link with thesecond portable terminal 300 according to the result.

Upon establishing the WLAN link with the second portable terminal 300,the controller 370 controls performing a corresponding operationaccording to a user request (operation 521). For example, the controller370 may transmit (stream) data according to user selection to the secondportable terminal 300 with which the WLAN link is established.

FIGS. 6 to 9 are diagrams illustrating examples of an operation screenof a first portable terminal according to an exemplary embodiment.

FIGS. 6 to 9 illustrate that a first user initiates a service forestablishing the WLAN link using a WLAN connection button 600 whileconfirming a document through a document viewer application as shown inFIG. 6.

FIG. 9 illustrates that the first user transmits (or streams) the musicto a second user when the first user establishes a WLAN link with atleast one second user selected from the contact list as shown in FIG. 7.That is, FIGS. 6 to 9 illustrate an operation when a music applicationis executed to share the music with another user located at aneighboring zone while the first user reads the document based on adocument view application. According to exemplary embodiments of FIGS. 6and 7, the first user may directly share a read document with the seconduser by a document view application or may directly share a listenedmusic with the second user by the music playback application.

FIG. 6 illustrates an example of a screen of the first portable terminal100 when a user of the first portable terminal 100 executes a connectionapplication. As shown in FIG. 6, the connection application is adocument view application. That is, FIG. 6 illustrates a state where theuser executes the document view application and confirms a documentusing the executed document view application. Upon the execution of thedocument view application, a function of the connection application,that is, an operation of establishing the WLAN link may be automaticallyperformed. A separate WLAN connection button 600 is provided at oneregion of a screen of the document view application, and accordingly anoperation for establishing the WLAN link may be initiated. The WLANconnection button 600 is illustrated as an icon in FIG. 6, but may beprovided as text, or a combination of an icon and text according to animplementation.

Accordingly, the first portable terminal 100 executes a document viewapplication according to an operation scheme of the connectionapplication, or receives contact information related to a user of thefirst portable terminal 100 from the contact server 200 through thecellular network 400 when establishment of the WLAN link is requested ona screen of the document view application according to the WLANconnection button 600.

The first portable terminal 100 displays a contact list screen as shownin FIG. 7 using the received contact information. That is, a screen ofthe first portable terminal 100 shown in FIG. 6 is converted to a screenshown in FIG. 7 according to reception of information.

As shown in FIG. 7, the first portable terminal 100 display a contactlist composed of contact information located at a neighboring zone ofthe user below an item <Nearby>. That is, when providing the contactlist, contact information with respect to the second portable terminal300 located in a zone neighboring a location of the first portableterminal 100 may be provided. The contact list may include contactinformation by specific groups according to user setting below an item<Group>, and may be indicated on a screen according to user input (e.g.,scroll).

The user may select contact items 710 of Lindsey Yoon and Nicholas Houltfrom a contact list displayed on a screen in order to form a WLAN linkwith Lindsey Yoon and Nicholas Hoult.

The user may input an <Invite> button 730 in order to request WLANconnection with selected portable terminals, that is, second portableterminals 300 of Lindsey Yoon and Nicholas Hoult. Then, according to the<Invite> button 730 input of the user, a screen of first portableterminal 100 shown in FIG. 7 may be converted into a screen as shown inFIG. 8.

FIG. 8 illustrates an example of a screen of the first portable terminal100 while the first portable terminal 100 establishes the WLAN link withthe second portable terminal 300. That is, when the first portableterminal 100 establishes the WLAN link, a state window 850 indicatingthat the first portable terminal 100 connects to the second portableterminal 300 may be displayed on a screen of the first portable terminal100 as illustrated in FIG. 8. The state window 850 may be displayed on aseparate screen as illustrated in FIG. 8 or may be displayed on a screenof FIG. 7 in the pop-up form. The first portable terminal 100 may outputthe sound into which a partial security key is loaded through a speaker341 together with display of a screen as described above, and may waitfor reception of a WLAN connection request from the second portableterminal 300.

If the first portable terminal 100 connects with the second portableterminal 300, that is, when a WLAN link is established, a screen of thefirst portable terminal 100 may be converted into a previously displayedscreen as illustrated in FIG. 7, and an execution screen of anotherapplication (e.g., music playback application) according to user requestmay be displayed like a screen of the first portable terminal 100 shownin FIG. 9. That is, the user may execute a music playback applicationsharing the music with Lindsey Yoon and Nicholas Hoult at a neighboringzone in which a WLAN link is established.

As shown in FIG. 9, if the WLAN link is established with the secondportable terminal 300 through the WLAN 400, the first portable terminal100 may execute a music playback application corresponding to a userrequest. The music playback application may transmit the music selectedby the user of the portable terminal 100 to the second portable terminal300 through the WLAN link in a streaming operation. That is, the firstportable terminal 100 may stream the music to Lindsey Yoon and NicholasHoult between which the WLAN link is established.

If the WLAN link is established, the first portable terminal 100 and thesecond portable terminal 300 does not require use of an interface for amobile communication network for exchanging data with each other.Accordingly, the first portable terminal 100 and the second portableterminal 300 may deactivate a communication function through a mobilecommunication network after the WLAN link is established.

FIG. 10 is a flow chart illustrating a control method when a portableterminal operates as a receiver portable terminal according to anexemplary embodiment.

Referring to FIG. 10, when receiving a connection request message from acontact server 200 (operation 1001), the controller 370 may display aselection menu confirming whether to connect with the first portableterminal 100 with reference to the connection request message on ascreen (operation 1003).

The controller 370 determines whether a connection approval input of theuser is received in the selection menu (operation 1005).

If receiving a connection rejection input of the user in the selectionmenu (NO of operation 1005), the controller 370 controls performing acorresponding operation (operation 1007). For example, the controller370 may return to an operation before the selection menu is displayedand may display a previous screen. For example, if an image beforedisplay of the selection menu is displayed, a corresponding image isagain displayed. If a game is executed, a corresponding game screen maybe again displayed.

If the connection approval input is received in the selection menu (YESof operation 1005), the controller 370 turns-on a microphone 343(operation 1009). When the microphone 343 is turned-on, the controller370 may start counting a receiving waiting time. The receiving waitingtime indicates a time waiting an input of a sound output from the firstportable terminal 100, and a waiting time may be set to various valuesaccording to user input.

The controller 370 determines whether the sound is received (operation1011). The controller 370 may check whether a sound output from thefirst portable terminal 100 is input through the microphone 343. Thecontroller 370 determines whether the input sound includes a partialsecurity key. If the input sound does not include the partial securitykey, the process goes to operation 1013.

When the sound is not received (NO of operation 1011), the controller370 determines whether the receiving waiting time is terminated(operation 1013). If the receiving waiting time is not terminated (NO ofoperation 1013), the controller 370 goes to operation 1011 and repeatsthe above-described procedures. If the receiving waiting time isterminated (YES of operation 1013), the controller 370 turns-off themicrophone 343 (operation 1015). The controller 370 may controlperforming a corresponding operation after the microphone is turned-off(operation 1025). For example, the controller 370 may control screendisplay of a previous step.

When the sound is received (YES of operation 1011), the controller 370acquires a partial security key (operation 1017). If the sound outputfrom the first portable terminal 100 is input through the microphone343, the controller 370 may acquire a first partial security key fromthe connection request message, and may acquire a second partialsecurity key from the sound. FIG. 10 illustrates that the first partialsecurity key and the second partial security key are acquired when thesound is received, but the first partial security key may be acquiredwhen the connection request message is received, when a connectionapproval input according to the selection menu is received, or when themicrophone 343 is turned-on.

The controller 370 combines the second partial security key with thefirst partial security key to generate one second security key(operation 1019). The controller 370 requests WLAN connection to thefirst portable terminal 100 using the connection information of theconnection request message and the second security key (operation 1021).That is, the controller 370 may request the WLAN connection to the firstportable terminal 100 with reference to the connection information, andmay transmit the second security key as a security key for requestingthe WLAN connection. The controller 370 may identify a first portableterminal 100 having transmitting a sound from connection information ofthe first portable terminal 100 acquired upon reception of a connectionrequest message.

According to a WLAN connection request approval of the first portableterminal 100, the controller 370 establishes the WLAN link with thefirst portable terminal 100 (operation 1023). For example, to establishthe WLAN link, the controller 370 may request WLAN connection to thefirst portable terminal 100 through a WLAN interface. Accordingly, whena WLAN function is turned-off, the controller 370 may activate a WLANfunction of the second portable terminal 300.

Upon establishment of the WLAN link with the first portable terminal100, the controller 370 controls performing a corresponding operation(operation 1025). When receiving data transmitted (streamed) from thefirst portable terminal 100 through the WLAN link, the controller 370may play the received data. The controller 370 determines whether anapplication ID is included in the connection information of theconnection request message. When the application ID is included in theconnection information of the connection request message, the controller370 may execute a connection application designated by the applicationID. The controller 370 may use various services (e.g., music streaming)using the executed connection application together with the firstportable terminal 100.

FIGS. 11 to 13 are diagrams illustrating examples of an operation screenof a second portable terminal according to an exemplary embodiment.

FIG. 11 illustrates an example of a screen of the second portable 300when the contact server 200 pushes the connection request message to thesecond portable terminal 300 through a cellular network 400. It isassumed that a user (e.g., DJ Kevin) of the first portable terminal 100connects with a user of the second portable terminal 300 through theWLAN 400 when a background is displayed on the second portable terminal300.

As shown in FIG. 11, when the contact server 200 pushes the connectionrequest message to the second portable terminal 300 in response to arequest from the first portable terminal 100, the second portableterminal 300 displays a selection menu 110 on a screen in a pop-up form.That is, the second portable terminal 300 may display a menu forconfirming whether to accept invitation of the first portable terminal100.

Since the first portable terminal 100 and the second portable terminal300 register user information (e.g., contact point, user name) to eachother, if the invitation is requested from the first portable terminal100, the second portable terminal 300 outputs user information of thefirst portable terminal 100 so that the user of the second portableterminal 300 may know that a user requesting invitation through theoutput user information is a user (e.g., DJ Kevin) of the first portableterminal 100. The first portable terminal 100 may provide metadata(e.g., information indicating a type of content which the first portableterminal 100 will transmit (stream)) capable of identifying contentstransmitted (streamed) when requesting invitation to the second portableterminal 300.

Accordingly, if the invitation is received from the first portableterminal 100, the second portable terminal 300 may display a selectionmenu 1100 including user information (e.g., DJ Kevin) of the firstportable terminal 100, contents information, and a <Join> and <Ignore>buttons for receiving a selection of connection approval or rejection,in the pop-up form. The number and types of items provided through theselection menu 1100 may be changed according to the implementation.

When the user selects (e.g., touches) an <Ignore> button on theselection menu 1110 in the screen of the second portable terminal 300,the screen of the second portable terminal 300 may return to a previousscreen, that is, a background screen. When the <Ignore> button isselected, the second portable terminal 300 may transmit a rejectionmessage rejecting connection to the first portable terminal 100.

If the user selects (e.g., touches) a <Join> button on the selectionmenu 1100 in the screen of the second portable terminal 300, the screenof the second portable terminal 300 may be converted as shown in FIG.12.

FIG. 12 illustrates an example of a screen of the second portableterminal 300 while the second portable terminal 300 establishes the WLANlink with the first portable terminal 100. As shown in FIG. 12, whilethe second portable terminal 300 establishes the WLAN link with thefirst portable terminal 100, a state window 1200 indicating that thesecond portable terminal 300 connects with the first portable terminal100 through the WLAN may be displayed on a screen of the second portableterminal 300. The state window 1200 may be displayed on a separatescreen as shown in FIG. 12, or may be displayed on a screen of FIG. 11in the pop-up form. That is, the state window 1200 shown in FIG. 12 maybe displayed on a background screen instead of the selection menu 1100of FIG. 11 in the pop-up form. The second portable terminal 300 maygenerate a second security key together with display of the screen asdescribed above, and may request WLAN connection to the first portableterminal 100 based on the second security key and the connectioninformation.

Meanwhile, if the first portable terminal 100 connects with the secondportable terminal 300, that is, when a WLAN link is established, ascreen of the first portable terminal 100 may be converted into apreviously displayed screen as illustrated in FIG. 11, and an executionscreen of another application according to a request from the firstportable terminal 100 may be displayed like a screen of the secondportable terminal 300 shown in FIG. 13.

FIG. 13 illustrates a screen which the second portable terminal 300executes a corresponding connection application (e.g., music playbackapplication) with reference to an application ID included in theconnection information after connecting with the first portable terminal100 through the WLAN. That is, as shown in FIG. 13, the second portableterminal 300 may receive and display a music file transmitted (streamed)from the first portable terminal 100. For example, when the user selectsa <Join> button from the selection menu 1100, the second portableterminal 300 may execute a music playback application. The secondportable terminal 300 may play a music file transmitted (or streamed)from the first portable terminal 100 through a music playbackapplication to display a music playback screen as shown in FIG. 13.

If the WLAN link is established, the first portable terminal 100 and thesecond portable terminal 300 do not require use of an interface for amobile communication network for exchanging data with each other.Accordingly, the first portable terminal 100 and the second portableterminal 300 may deactivate a communication function through a mobilecommunication network after the WLAN link is established.

The foregoing exemplary embodiments may be implemented in an executableprogram command form by various computer means and be recorded in acomputer-readable recording medium. The computer-readable recordingmedium may include a program command, a data file, and a data structureindividually or a combination thereof. In the meantime, the programcommand recorded in a recording medium may be specially designed orconfigured or be known to a person having ordinary skill in a computersoftware field to be used. The computer-readable recording mediumincludes Magnetic Media, such as hard disk, floppy disk, or magnetictape, Optical Media such as Compact Disc Read Only Memory (CD-ROM) orDigital Versatile Disc (DVD), Magneto-Optical Media such as flopticaldisk, and a hardware device such as ROM, RAM, and flash memory, storingand executing program commands. Further, the program command includes amachine language code created by a compiler and a high-level languagecode executable by a computer using an interpreter. The foregoinghardware device may be configured to be operated as at least onesoftware module to perform an operation, and vice versa.

As described above, according to the method and the system forestablishing a WLAN link between portable terminals of an exemplaryembodiment, the user may establish a WLAN link representing reinforcedsecurity stability by only a simple operation. An exemplary embodimentmay divide a security key, in establishing a WLAN link between portableterminals, and provide the divided security keys separately.

Particularly, a transmitter portable terminal initiating a service maydivide one security key into at least two such as a first partialsecurity key and a second security key, and output the divided partialsecurity keys through the cellular network and a sound. Then, thereceiver portable terminal combines the second partial security keyacquired through the sound with the first partial security key acquiredthrough the cellular network to generate a security key for establishingthe WLAN link with the transmitter portable terminal.

As described above, when providing the security key for establishing theWLAN link between the portable terminals, a part of the security key isprovided through the cellular network and a remaining part of a securitykey is provided through the sound, so that exposure of the security keydue to external hacking of the contact server and unintendedestablishment of the WLAN due to unintended sound reception of anotheruser can be prevented. That is, when establishing the WLAN link betweenthe portable terminals, reinforced security stability can be provided,and illegal establishment of the WLAN link from unintended users orexternal hacking can be prevented.

Exemplary embodiments may be implemented in various types of portableterminals and various devices corresponding thereto. In addition,exemplary embodiments can improve convenience, usability, andcompetitive force of the portable terminals by implementing optimalenvironments for establishing the WLAN link.

The described-above exemplary embodiments and advantages are merelyexemplary and are not to be construed as limiting. The present teachingcan be readily applied to other types of apparatuses. The description ofexemplary embodiments is intended to be illustrative, and not to limitthe scope of the claims, and many alternatives, modifications, andvariations will be apparent to those skilled in the art.

What is claimed is:
 1. A method of establishing a wireless local areanetwork (WLAN) link in a portable terminal, the method comprising:transmitting a connection request message including a first partialsecurity key being a portion of a first security key to a secondportable terminal through a cellular network, by a first portableterminal; outputting a sound including a second partial security keybeing a remaining portion of the first security key, after transmittingthe connection request message; receiving a request of a WLAN connectionincluding a second security key from the second portable terminal havingreceived the sound through a WLAN; and establishing the WLAN link withthe second portable terminal when the second security key corresponds tothe first security key.
 2. The method of claim 1, wherein thetransmitting the connection request message comprises: acquiring contactinformation of a plurality of second terminals of a neighboring zone;displaying a contact list based on the contact information of theplurality of second terminals; and receiving an input for selecting atleast one second portable terminal from the contact list.
 3. The methodof claim 2, wherein the acquiring the contact information comprisesacquiring the contact information from a contact server, by the firstportable terminal.
 4. The method of claim 2, wherein the acquiring thecontact information comprises acquiring the contact information from amemory of the first portable terminal.
 5. The method of claim 3, furthercomprising transmitting the connection request message to the contactserver, by the first portable terminal, wherein the contact serverpushes the connection request message to the second portable terminal.6. The method of claim 1, further comprising dividing the first securitykey into the first partial security key and the second partial securitykey.
 7. The method of claim 1, wherein the outputting the soundcomprises: determining an output level of the sound into which thesecond partial security key is loaded; and outputting the soundaccording to the determined output level.
 8. The method of claim 1,further comprising receiving a user input for establishing the WLANlink.
 9. A method of establishing a wireless local area network (WLAN)link in a portable terminal, the method comprising: receiving aconnection request message from a contact server through a cellularnetwork via a push operation, by a second portable terminal; turning-ona microphone for receiving a sound output from a first portableterminal, in response to the connection request message; receiving thesound output from the first portable terminal through the microphone;acquiring a first partial security key according to the connectionrequest message and a second partial security key according to thesound; combining the second partial security key with the first partialsecurity key to acquire a security key; and requesting a WLAN connectionto the first portable terminal using the acquired security key.
 10. Themethod of claim 9, wherein the turning-on the microphone comprises:displaying a selection menu for receiving an approval of the WLANconnection, when the connection request message is received; andturning-on the microphone when the approval of the WLAN connection isinput.
 11. The method of claim 9, further comprising acquiringconnection information for the WLAN connection from the connectionrequest message.
 12. The method of claim 11, wherein the requesting theWLAN connection comprises: identifying the first portable terminaltransmitting the connection request message based on the connectioninformation; and transmitting the security key to the first portableterminal to request the WLAN connection.
 13. The method of claim 9,wherein the requesting the WLAN connection comprises requesting the WLANconnection using one of the cellular network and a WLAN.
 14. A firstportable terminal comprising: a memory which stores a program; and acontroller which executes the program to establish a wireless local areanetwork (WLAN) link with a second portable terminal, wherein the programcomprises commands which, when executed by the controller, cause thecontroller to execute a method comprising: transmitting a connectionrequest message including a first partial security key being a portionof a first security key to the second portable terminal through acellular network; outputting a sound including a second partial securitykey being a remaining portion of the first security key, aftertransmitting the connection request message; receiving a request of aWLAN connection including a second security key from the second portableterminal having received the sound through a WLAN; and establishing theWLAN link with the second portable terminal when the second security keycorresponds to the first security key.
 15. The first portable terminalof claim 14, wherein the outputting the sound comprises: determining anoutput level of the sound into which the second partial security key isloaded; and outputting the sound according to the determined outputlevel.
 16. The first portable terminal of claim 14, wherein thetransmitting the connection request message comprises: displaying acontact list corresponding to a plurality of second portable terminals,based on contact information of the plurality of second portableterminals of a neighboring zone acquired from a contact server; andtransferring the first partial security key and the second partialsecurity key to a respective second portable terminal through thecellular network and the sound, respectively, when receiving an inputfor selecting the respective second portable terminal from the contactlist.
 17. A first portable terminal comprising: a memory which stores aprogram; and a controller which executes the program to controlestablishment of a wireless local area network (WLAN) link with a secondportable terminal, wherein the program comprises commands which, whenexecuted by the controller, cause the controller to execute a methodcomprising: turning-on a microphone for receiving a sound output fromthe second portable terminal in response to a connection request messagereceived from a contact server via a push operation; receiving the soundoutput from the second portable terminal through the microphone;acquiring a first partial security key according to the connectionrequest message and a second partial security key according to thesound; combining the second partial security key with the first partialsecurity key to acquire a security key; and requesting WLAN connectionto the second portable terminal using the acquired security key.
 18. Thefirst portable terminal of claim 17, wherein the turning-on themicrophone comprises: displaying a selection menu for receiving aconfirmation that the WLAN connection is approved, when receiving theconnection request message; and turning-on the microphone to receive thesound from the second portable terminal when the WLAN connection isapproved.
 19. The first portable terminal of claim 18, wherein theconnection request message comprises the first partial security keybeing a portion of the security key and connection information for theWLAN connection, and the method further comprises: identifying thesecond portable terminal transmitting the connection request messagebased on the connection information; and transmitting the security keyto the second portable terminal to request the WLAN connection.
 20. Anon-transitory computer-readable recording medium storing a programthat, when executed by a computer, causes the computer to execute amethod comprising: transmitting partial security keys divided from afirst security key through a cellular network and a sound, respectively;combining the partial security keys received through the cellularnetwork and the sound with each other to generate a second security key;and establishing a wireless local area network link using the firstsecurity key and the second security key.